Contents

Climate[edit]

The climate of the Pampas is generally temperate, gradually giving way to a more subtropical climate in the north, and to a semi-arid climate on the western fringes (e.g. San Luis Province and western La Pampa Province). Summer temperatures are more uniform than winter temperatures, generally ranging from 28 to 33 °C (82 to 91 °F) during the day. However, most cities in the Pampas occasionally have high temperatures that push 38 °C (100 °F). This occurs when a warm, dry northerly wind blows from southern Brazil. Autumn arrives gradually in March, and peaks in April and May. In April, highs will range from 20 to 25 °C (68 to 77 °F) and lows from 9 to 13 °C (48 to 55 °F). The first frosts arrive in mid-April in the south, and in late May or early June in the north.

Winters are generally mild, although cold waves do occur. Normal temperatures range from 12 to 19 °C (54 to 66 °F) during the day, and from 1 to 6 °C (34 to 43 °F) at night. With strong northerly winds, days of over 25 °C (77 °F) can be recorded almost everywhere, whereas during cold waves, high temperatures can be only 6°C (43F). Frost occurs everywhere in the Pampas, although it is much more frequent in the southwest, and less so around the Parana and Uruguay rivers. Temperatures under −5 °C (23 °F) can occur everywhere, whereas values of −10 °C (14 °F) or lower are confined to the south and west. Snow never falls in the northernmost third, and is rare and light elsewhere, except for exceptional events where depths have reached 30 cm (12 inches).

Springs are very variable, it is warmer than fall in most areas (especially in the west) but significantly colder along the Atlantic. Violent storms are more common, as well as wide temperature variations: days of 35 °C (95 °F) can give way to nights of under 5 °C (41 °F) or even frost, all within only a few days.

Precipitation ranges from 1,200 millimetres (47 in) in the northeast, to about 500 millimetres (20 in) in the southern and western edges. In the west, it is highly seasonal, with some places recording averages of 120 millimetres (4.7 in) monthly in the summer, and only 20 millimetres (0.8 in) monthly in the winter. The eastern areas have small peaks in the fall and in the spring, with relatively rainy summers and winters that are only slightly drier. However, where summer rain falls as short, heavy storms, winter rain falls mostly as cold drizzle, so that the amount of rainy days is fairly constant. Violent thunderstorms are common in the spring and summer

Vegetation[edit]

Frequent wildfires ensure that only small plants such as grasses flourish, and trees are rare. The dominant vegetation types are grassy prairie and grass steppe in which numerous species of the grass genus Stipa are particularly conspicuous. "Pampas Grass" (Cortaderia selloana) is an iconic species of the Pampas. Vegetation typically includes perennial grasses and herbs. Different strata of grasses occur because of gradients of water availability.

Winters are cool to mild and summers are very warm and humid. Rainfall is fairly uniform throughout the year but is a little heavier during the summer. Annual rainfall is heaviest near the coast and decreases gradually further inland. Rain during the late spring and summer usually arrives in the form of brief heavy showers and thunderstorms. More general rainfall occurs the remainder of the year as cold fronts and storm systems move through. Although cold spells during the winter often send nighttime temperatures below freezing, snow is quite rare. In most winters, a few light snowfalls occur over inland areas.

Central Argentina boasts a successful agricultural business, with crops grown on the Pampas south and west of Buenos Aires. Much of the area is also used for cattle and more recently to grow vineyards in the Buenos Aires wine region. These farming regions are particularly susceptible to flooding during the thunderstorms. In the Pampas the weather averages out to be 77 °F (25 °C) round year.

View of the northern Pampas grain belt

Lake Gómez, near Junín, in the heart of the Pampas grain belt. The Pampa extends from the foothills of the Andes Mountains on the west to the Atlantic Ocean on the east. The region is peppered with finger lakes, holdovers from the last Ice Ages.